As I written in a comment below:
This summer a very intersting book was published in UK. The book might explain WHY so many never learnt basic facts nor was given the chance to understand basic first, deep understanding next in order to learn how to go on to understanding more than bits and pieces.

Daisy Christodoulou did a tough research in true Theories of Science-maner writing: Exploding Seven Myths about Education….
Guess what. In the 1960’s the wave of returning to Rousseau’s thoughts about Freedom and Learning started to have a major impact on teaching and learning in UK as well as US. (Sweden is an other example 1960-talet fortsätter skada den svenska skolan, SvD ledarsidan 20 december 2014

So what was the Seven Myths:

* Facts prevent understanding
* Teacher-led instruction is passive
* The 21st century fundamentally changes everything
* You can always just look it up
* We should teach transferable skills
* Projects and activities are the best way to learn
* Teaching knowledge is indoctrination.

How come this started in the 1960’s? Well I myself found three major reasons: In 1960’s the first of the War Children and those who like me were born in 1940’s grow up. A numerous number who started having children compared to days before WWII. The well educated teacher my own generation had had, had to first be ”dublicated” and from late 70’s replaced so many more teachers had to be ”found” and educated to make it possible to teach all the newborn children when growing up. But the third factor I myself found is the same as what caused the revolts around the World in 1968 – too many people became lefties… (Need I explain?)

Thus when the children of 1960’s and early 70’s grow up believing not only in an unfairness when some had high grades and some low the answer seemed to come from Sociology Studies of Society. Life isn’t always fair but some believed that it was a Human Right not only to have the basic school education that’s written in Human Rights but to have it anyway and that no one ought to stop them from having that no matter if they didn’t had proper understanding enough to go on to higher studies.
What we had, unfortunatly in my opinion is a less educated growing number of students at University’s from there on…. Quantity instead of Quality…

From a review:But as Christodoulou is at pains to point out, what looks like a peculiarly contemporary antipathy to teaching knowledge, ‘this endless transmission of information’ as national curriculum architect Mick Waters disparagingly put it in 2012, actually has a rather long ancestry. ‘It is an intellectual legacy of the Romantic era’, she tells me, ‘with Rousseau its forefather. It’s not a recent phenomenon.’

Indeed, as Seven Myths makes clear, there has long been a tradition of thought in which teaching children facts, inculcating them, sometimes by rote, with particular areas of knowledge, has been viewed as detrimental to the child. As Rousseau put it in Emile, ‘What is the use of inscribing on [children’s] brains a list of symbols which mean nothing to them?’. Rousseau even went so far as to call such teaching methods ‘immoral’ on the grounds that fact-learning robs children of childhood. Again in the late nineteenth century, American philosopher John Dewey argued that teaching children maths or the dates of historical events, rather than letting them learn through their own experience, made them passive, the recipients of ‘a mass of meaningless and arbitrary ideas imposed from without’. And then, of course, there is Gradgrind, the Charles Dickens grotesque in Hard Times who, by famously insisting that ‘Facts alone are wanted in life’, left his pupils emotionally stunted – hardly a ringing endorsement of a knowledge-based education by that most canonical of authors.Exploding Seven Myths about Education, Daisy Christodoulou , a one-time University Challenge winner, UK secondary-school teacher, and now a researcher at ARK school. Review written by Deputy Editor Tim Black on spiked-on-line.com
—- my comment also is the main reason why I myself, from beginning Liberal, became a Conservative voter

Global atmospheric carbon dioxide concentrations from Oct. 1 through Nov. 11, as recorded by NASA’s Orbiting Carbon Observatory-2. Carbon dioxide concentrations are highest above northern Australia, southern Africa and eastern Brazil. Preliminary analysis of the African data shows the high levels there are largely driven by the burning of savannas and forests. Elevated carbon dioxide can also be seen above industrialized Northern Hemisphere regions in China, Europe and South America and Africa. Image credit: NASA/JPL-Caltech

The first global maps of atmospheric carbon dioxide from NASA’s new Orbiting Carbon Observatory-2 mission demonstrate its performance and promise, showing elevated carbon dioxide concentrations across the Southern Hemisphere from springtime biomass burning.

At a media briefing today at the American Geophysical Union meeting in San Francisco, scientists from NASA’s Jet Propulsion Laboratory, Pasadena, California; Colorado State University (CSU), Fort Collins; and the California Institute of Technology, Pasadena, presented the maps of carbon dioxide and…